Sucker rod swivel



Oct; 1-1, 1938. E. HOLLYFIELD 2,132,477

SUCKER ROD SWIVEL Flled Nov 30 1936 INVENTOR ED HOLLYF/ELD BYQMM 6M ATTORNEYS I Patented Oct. 11, 1938 f UNITED STATES SUCKER ROD SWIVVEV-L Ed Hollyfield,

El Dorado, Ark.

Application November 30, 1936, Serial No. 113,399

6 Claims.

The invention relates to a sucker rod swivel for use in oil well pumps to prevent torsion stresses in, and unscrewing of, sucker rods and at the same time to permit rotational displacement of the pump plunger whereby wear is distributed about the periphery of the plunger.

In the pumping of oil wells a sucker rod transmits reciprocatory motion from the pumping mechanism at the earths surface to the pump in the lower levels of the well. As pumping continues torsional stresses in the sucker rod may arise because of mechanical conditions in the pump assembly or such stresses may exist at the time of installation of the pump. These stresses may in time lead to unscrewing of the sucker rod which, of course, necessitates removal of the tubing and rod to reconnect the sucker rod sections.

It is an object of the invention to provide sucker rod swivel to be connected in the sucker rod string to relieve the torsional stresses in the string and hence prevent unscrewing of the sucker rod sections. 7

It is also an object of the invention to provide in a sucker rod assembly a novel and improved sucker rod swivel to relieve torsional stresses and to permit turning of the reciprocating pump ele- -ment while in operation, thereby reducing unevenness of wear.

A further object is to provide a swivel that is enclosed, themoving parts thereof being encased in oil whereby friction and resistance to turning are minimized.

A further object is to provide a new and improved construction that effectively swivels the parts connected thereto but which may be made rigid without access thereto if, at any time, such rigid connection'is necessary or desirable.

It is also an object of the invention to provide a device of the above indicated characteristics which is simple and substantial in construction, which can be manufactured economically and which is so constructed that a minimum of wear takes place.

Other objects, together with the foregoing, will be apparent from the following description and the drawing which illustrates an embodiment of the invention, it being understood that the description is for purposes of illustration only, and that the invention is to be construed only in view of the prior art and the appended claims. In the drawing:

Fig. 1 is a sectional elevation of the device of the invention.

Fig. 2 is a sectional viewof the coupling connection at the upper end of the swivel.

Fig. *4 is a sectional view on line 4+4 of Fig. 1.

Referring to Fig. l, numeral I6 designates the body of the device of the invention. This body is provided with a cylindrical bore II. A partition I2, which divides the cylindrical body into. two parts, is provided with a central opening I3 and presents a downwardly facing shoulder I,4..

Fig. 3 is a sectional view on line 3-3 of Fig. 1. v

A piston I5 slidably, fits within the bore II and is provided with a reduced extension I6 which passes through opening I3 and projects beyond the body I6. This extension may be formed integral with the piston I5 or it may, as shown, he made separate and comprise the stem portion I6, a'flange portion I1, and a' threaded portion I8, whereby the extension and piston may be rigidly interconnected to form a composite unit. An anti-friction bearing I9 is positioned about the extension I6 and is adapted to receive stresses between shoulder I4 and flange I'I.

As is best seen in Fig. 3, the lower end of piston I5 is provided with a recess 20 of polygonal cross-section for a purpose that will be made apparent. This recess is shown as being a square cross-section but it isap-parent that any desirable cross-section may be provided so long as the intended function is performed.

The body member ID is provided with threads 21 at its lower end. A plug 22 of special construction is provided with complementary threads and is threadably secured to the body member to form a closure for the bore II. Extending upwardly from plug 22 andunitary therewith is a projection 23'which terminates below the end of piston I5 thus leaving a small gap 24. As is best seen in- Fig. 4, projection 23 is also of polygonal cross-section in order that this projection may fit within recess 20 for a purpose that will be made apparent by the description of the assembly and operation of the device of the invention.

A packing material '25 of any suitable nature is placed about stem' I6 above partition I2 and a threaded gland member 26 is screwed into the body member ID to form a fluid tight seal between the stem I6 and the body I0. A lubricant 30 of suitable viscosity seals all available space in the swivel below the packing 25.

A coupling 9, Fig. 2, is secured to stem I6 through threads 8 and is locked thereto by means of a lock nut I. The opposite end of coupling 9 is provided with threads 6 to form a box and pin coupling with the sucker rod above the swivel. Plug 22 is provided with threads 21 whereby a similar connection may be made with the sucker rod below the swivel.

The assembly and operation of the device of the invention is as follows:

The piston assembly is placed in barrel I 0 with the anti-friction bearing l9 in place between shoulder I4 and flange [1. Packing 25 and gland 26 are then placed about stem l6 and the parts thus assembled are held in inverted position. Sufficient lubricant is placed in the chamber presented by the open bore II to fill all the space that will remain when plug 22 is tightly secured in place.

by the swivel is made fluid tight. The swivel is attached in a sucker rod string in an obvious manner.

It is apparent that the enclosed lubricant will provide lubrication that minimizes wear. The lubricant also serves another important function. In the normal operation of the device forces acting on the. swivel maintain pressure upon the bearing l9. If, however, the unit is placed under a .compressive stress there is a slow leakage of the lubricant past piston I5 and the piston will move downward into the body of oil.. A succeeding reversal of the stress will again cause the piston'to move upward to its original position without impact resulting from the reversal of the stress. This condition is such as may arise in a normal use of the device. however, when-the rods and/or plunger in the lower levels :of. the wellbecome sanded up orstuck and it is necessary to remove the pump tubing and sucker rods from the well for repairs.

'In such event it is desirable toturn the sucker rod and hence to back off or unscrew the same at some point in the tubing. This being done, the tubing is then withdrawn from the well until the rods'are reached when the sameare unscrewed again in like manner until all of the tubing and rods are removed and freed;

In order to lock the swivel against turning to effect unscrewing of the sucker rod below the swivel a downward pressure is applied thereto whereby the lubricant 30 slowly leaks past piston [5- which -moves downwardly until projection 23 fits within-recess 2B. The upper and lower ends of the swivel are then rigidly interconnected making it possible to screw or unscrew the rods without first removing the swivel.

In accordance with the foregoing descriptionit is apparent that :the invention provides a sucker row swivelthat functions effectively to prevent unscrewing or the backing off of the sucker rod. The device also distributes wear-of the reciprocating parts of the pump, and-wear on the tubing, by permitting rotation thereof during pumping operations.

The device of the invention may be used at any desirable point in the sucker rod string; The preferred location'has been found to be near the top of the well. For example, seventy-five or one hundred feet from the top. Such assembly is understood to be illustrative only of the use of Plug 22 is then screwed in place where- Occasions may arise,

the device and applicant does not desire it to be limited thereby.

What is claimed is:

1. A sucker rod swivel comprising a body portion having a downwardly facing shoulder therein, a piston within said body portion and having a cavity in the bottom thereof, a thrust bearing between said shoulder and said piston to receive the thrust between said shoulder and said piston, a plug in the end of said body and means on said plug for engagement With the cavity in said piston for locking the sections against turning movement with relation to each other.

2. A sucker rod swivel comprising a body, a partition in'said body, an imperforate piston below said partition, a thrust bearing between said piston and said partition, means for closing the body to confine a lubricant therein, and means for connecting said piston and said body respectively to sucker rod sections to attach the swivel in a sucker rod string.

3. A sucker rod swivel comprising a cylindrical body member having a bore therein, a partition in said. bore, an imperforate piston in said bore below the partition, a stem on said piston extending through an opening in said partition and adapted to be connectedto a sucker rod, closure means in the bodyfbelow said piston, and a lubricant within said body about said piston.

4. In a sucker rod swivel, a body, a piston rotatably mounted within said body, means for connecting sucker rod sectionsto said piston and said body, whereby said rod sections may rotate relative to each other, means for encasing a lubricant within said body about said piston, and means for locking said piston and body against relative turning movement when said piston isu moved downwardly through the lubricant in said body. r

5.. A sucker rod swivel including a tubular body, a plug sealing the lower end thereof,.a piston in said body, a sucker rod connecting member on said piston extending from the upper end of said housing, means on said body to sealabout said member whereby lubricant may be retained in said body, interengaging means between said piston and said plug acting to prevent relative rotation of said piston in said body when said piston is movedrelatively downward through the lubricant within thebody and means to connect said plug to a sucker rod section.

6. A sucker rod swivel including .a tubular body, a plug sealing the lower end thereof, an imperforate piston in said body, a sucker rod connecting member on said piston extending from the upper end of said housing, means on said body to seal about said member whereby lubricant may be retained in said body, an antifriction bearing between said sealingmeans and said piston, interengaging means between said piston and said plug acting to prevent relative rotation of said piston in said body when said piston is 

